Salt, sleep apnea linked to excessive night urination

Salt consumption and sleep apnea may be associated with nocturia, according to findings from two studies presented at the European Association of Urology.

Salt consumption

Tomohiro Matsuo, MD, from the department of urology at Nagasaki University School of Medicine, Japan, and colleagues provided 321 participants in Japan with written instructions on how to reduce salt intake. Participants’ urinary frequency and voided volume was also recorded before decreasing their salt intake and 12 weeks after initiation of decreased salt intake.

After 12 weeks, 223 participants lowered their mean salt intake from 10.7 g to 8 g (P < .001) per day. Their nocturnal polyuria index improved from 30.2% to 27.7% (P < .001) and nighttime frequency improved from 2.3 times to 1.4 times (P < .001). In addition, Core Lower Urinary Tract Symptom scores for urgency changed from 1 to 0.9 (P = .001), nocturia improved from 1.9 to 1.3 (P < .001), frequency during the day improved from 0.8 to 0.4 (P < .001), and the quality of life parameter improved from 3.6 to 2.7 (P < .001).

“This work holds out the possibility that a simply dietary modification might significantly improve the quality of life for many people,” Matsuo said in a press release.

Among the other 98 participants, the mean salt intake increased from 9.6 g to 11 g (P < .001) per day. Matsuo and colleagues found that among these participants, nighttime frequency increased from 2.3 times to 2.7 times (P < .001); nocturnal polyuria remained unchanged during the study period.

“Research generally focuses on reducing the amount of water a patient drinks, and the salt intake is generally not considered,” Marcus Drake, BM, BCh, MA, DM, FRCS, working group lead of the European Association of Urology Guidelines Office Initiative on Nocturia, said in the release. “Here we have a useful study showing how we need to consider all influences to get the best chance of improving the symptom.”

Sleep apnea

Sajjad Rahnama’i, MD, PhD, from Maastricht University in the Netherlands, and colleagues asked 256 patients being treated for obstructive apnea with continuous positive airway pressure, or CPAP, a series of questions about their nocturia incidents, medical history, and medications. Before beginning CPAP treatment, 69% of the patients had reported nocturia.

Researchers found that after the patients started to use the CPAP, nocturia was reduced in 65% of patients In addition, of the 77 patients who had indicated two episodes per night, 32 went the whole night without waking up.

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“This is the first study to show the true incidence of nocturia ... in patients who suffer from obstructive sleep apnea,” Rahnama’i said in a separate release. “It’s also the first study to show the size of the effect of positive pressure mask treatment in patients with obstructive sleep apnea on their nocturia symptoms.”

Drake said that although the link between breathing problems and nocturia may be surprising, it is a very real problem.

“To have a study showing the link, and the potential benefits of therapy, may help establish the treatment into routine clinical practice,” he said in the release. – by Janel Miller

References:

Degalliers S, et al. Abstract 566. Presented at: European Association of Urology Annual Meeting; March 24-28, 2017; London.

Matsuo, T, et al. Abstract 399. Presented at: European Association of Urology Annual Meeting; March 24-28, 2017; London.

Disclosure: Healio Family Medicine was unable to confirm the researchers’ relevant financial disclosures prior to publication.